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Passport
- Family
- Tetras
- Grows to
- 4 cm (1.6")
- Lives
- 6–8 years
- Temperament
- Peaceful
- Care
- Beginner
- Swims
- Mid-water
- Keep
- In a group of 8 or more
- Water
- 20–28 °C (68–82 °F)
Brazil
Care requirements
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On record for Lemon Tetra: adult size, lifespan, minimum tank, temperature, ph, hardness, minimum group, diet, care level, swim level, tank length.
A figure that is not on record is left out rather than guessed. One marked Suggested comes from keeping knowledge rather than a page.
- Minimum tank 76 L / 20.0 US gal
- pH 5–7.5
- Hardness 1–12 dGH
- Diet omnivore
- Tank length 80 cm minimum
Care notes written from general aquarium knowledge, not from the cited sources.
About
Lemon tetras are a slow burn. In the shop tank they're a pale, deep-bodied fish that most people walk past, and six months into a settled tank they're translucent yellow with a ruby-red eye and black-and-lemon edging along the fins.
That transformation is the whole point of the species, and it's why they get overlooked. Nobody buys the fish they'll eventually own.
Males compete constantly among themselves in temporary pecking orders, flaring at each other over females and position. None of it does any damage, and it's the reason a proper group of lemons is far more interesting to watch than a pair.
Tank setup
Give your lemons a well-planted tank with open water through the centre. They're deeper-bodied than most small tetras and they swim in the middle, so a tall thin tank suits them less than a long one.
Go dark on the substrate and moderate on the light. Yellow is a difficult colour to show off, and against pale gravel under a bright lamp a lemon tetra just looks colourless.
Add wood and leaf litter. The tannins take the edge off the lighting and the decomposing leaves grow the microscopic life that both adults and fry pick at.
Soft, slightly acidic water gets the best out of them, though farmed stock handles a fair range without complaint.
Feeding
Lemons are omnivores that eat almost anything, and they're less shy at feeding time than their washed-out appearance suggests.
Colour is where diet shows. The yellow deepens and the red eye brightens on a varied menu with regular live and frozen food — bloodworm, mosquito larvae, daphnia, moina. Fish kept on dried food alone stay pale, and their keepers assume that's just how the species looks.
Feed small amounts often. They graze rather than gorge.
Avoid: a dried-food-only diet, which is the single most common reason a lemon tetra never colours up.
Filtration and flow
Moderate flow is fine. Lemons come from minor tributaries, oxbows and flooded forest rather than fast water, but they're competent swimmers and a little movement doesn't bother them.
Keep the tank mature and the water changes regular. They're not delicate, but the fins are where neglect shows first — the black edging goes ragged before the fish looks ill.
Gentle filtration and botanicals suit the setup they look best in anyway.
With plants
Lemon tetras are safe with plants and won't touch them. No digging, no grazing, no uprooting.
Plant heavily and leave a swimming lane. The males need room to display and the lower ranked fish need somewhere to be, and dense planting round an open middle gives you both.
Fine-leaved plants are useful if you want spawning to happen on its own, which with this species it sometimes does.
Health
They're hardy and long-lived by small tetra standards, and there's no disease particularly associated with them.
Look at the fin edges as your early warning. The black-and-yellow banding is crisp on a healthy fish, and it dulls and frays before anything else goes wrong.
A lemon tetra that stays permanently pale in a mature tank isn't necessarily ill — it's usually underfed on variety, or kept in too small a group to bother displaying.
Breeding
Lemons scatter eggs and give no parental care, and in a heavily planted tank you'll occasionally find a fry that made it on its own.
For numbers, condition the group hard on live food, then move a male and a couple of females to a dim tank floored with mesh, marbles or moss. Slightly acidic water and the warm end of their range gets them going, usually by the next morning.
Pull the adults out once eggs are down. The fry are tiny and need infusoria or a micron-graded dry food before they can take baby brine shrimp, and rushing that step is what kills most attempts.
Tank mates
Avoid9
- Convict Cichlid Convict Cichlid grows to 15 cm against Lemon Tetra at 4 cm, big enough to eat it.
- Jewel Cichlid Jewel Cichlid grows to 15 cm against Lemon Tetra at 4 cm, big enough to eat it.
- Pictus Catfish Pictus Catfish grows to 12 cm against Lemon Tetra at 4 cm, big enough to eat it.
- Common Goldfish Common Goldfish is not safe with Lemon Tetra: common goldfish and tetras are a bad pairing.
- Demasoni Cichlid Demasoni Cichlid is not safe with Lemon Tetra: african cichlids and tetras are a bad pairing.
Only with care10
- Chinese Algae Eater Chinese Algae Eater is aggressive and Lemon Tetra is peaceful.
- Cherry Barb Lemon Tetra and Cherry Barb are an uneasy mix: barbs and tetras are a pairing to watch.
- Gold Barb Gold Barb is a risk to Lemon Tetra: barbs and tetras are a pairing to watch.
- Odessa Barb Lemon Tetra and Odessa Barb are an uneasy mix: barbs and tetras are a pairing to watch.
- Paradise Fish Paradise Fish is a risk to Lemon Tetra: large gouramis and tetras are a pairing to watch.
No conflict is recorded with the other 85 species in the database, so nothing to flag. 4 species are not covered at all, so they could not be judged either way.